1. Field of the Invention
This invention relates to plasma etching equipment and, more particularly, to a gas distribution system for a plasma etcher.
2. Prior Art
Previously, plasma etching equipment used to etch thin oxide films in semiconductor devices have had problems with contamination of a semiconductor device by polymer particles. Thin layers of polymer materials are deposited over the interior surface of a reaction chamber. The polymers are produced as a result of the chemical reactions involved in the oxide etching process. Gases for the plasma etching process are injected into the reaction chamber through gas inlet holes in a gas distribution plate, which is positioned within the reaction chamber directly over a semiconductor wafer mounted on a cathode structure. A plasma is formed in the reaction chamber and the plasma may even extend through the gas inlet holes and into the gas supply manifold so that polymer material is formed within the gas inlet holes and even in the gas manifold. Particles of polymer material formed in the gas supply manifold and in the gas inlet holes of the gas distribution plate break off and fall on a semiconductor wafer being etched. These particles contaminate the wafers and, consequently, reduce the yield obtained from a wafer.